/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.

 *

 * This software is licensed as described in the file COPYING, which

 * you should have received as part of this distribution. The terms

 * are also available at https://curl.se/docs/copyright.html.

 *

 * You may opt to use, copy, modify, merge, publish, distribute and/or sell

 * copies of the Software, and permit persons to whom the Software is

 * furnished to do so, under the terms of the COPYING file.

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY

 * KIND, either express or implied.

 *

 * SPDX-License-Identifier: curl

 *

 ***************************************************************************/

#include "curl_setup.h"

#if !defined(CURL_DISABLE_COOKIES) || !defined(CURL_DISABLE_ALTSVC) ||  \

  !defined(CURL_DISABLE_HSTS)

#ifdef HAVE_FCNTL_H

#include <fcntl.h>

#endif

#include "urldata.h"

#include "rand.h"

#include "fopen.h"

/* The last 3 #include files should be in this order */

#include "curl_printf.h"

#include "curl_memory.h"

#include "memdebug.h"

/*

 * Curl_fopen() opens a file for writing with a temp name, to be renamed

 * to the final name when completed. If there is an existing file using this

 * name at the time of the open, this function will clone the mode from that

 * file.  if 'tempname' is non-NULL, it needs a rename after the file is

 * written.

 */

CURLcode Curl_fopen(struct Curl_easy *data, const char *filename,

                    FILE **fh, char **tempname)

{

  CURLcode result = CURLE_WRITE_ERROR;

  unsigned char randsuffix[9];

  char *tempstore = NULL;

  struct_stat sb;

  int fd = -1;

  *tempname = NULL;

  *fh = fopen(filename, FOPEN_WRITETEXT);

  if(!*fh)

    goto fail;

  if(fstat(fileno(*fh), &sb) == -1 || !S_ISREG(sb.st_mode))

    return CURLE_OK;

  fclose(*fh);

  *fh = NULL;

  result = Curl_rand_alnum(data, randsuffix, sizeof(randsuffix));

  if(result)

    goto fail;

  tempstore = aprintf("%s.%s.tmp", filename, randsuffix);

  if(!tempstore) {

    result = CURLE_OUT_OF_MEMORY;

    goto fail;

  }

  result = CURLE_WRITE_ERROR;

  fd = open(tempstore, O_WRONLY | O_CREAT | O_EXCL, 0600);

  if(fd == -1)

    goto fail;

#ifdef HAVE_FCHMOD

  {

    struct_stat nsb;

    if((fstat(fd, &nsb) != -1) &&

       (nsb.st_uid == sb.st_uid) && (nsb.st_gid == sb.st_gid)) {

      /* if the user and group are the same, clone the original mode */

      if(fchmod(fd, (mode_t)sb.st_mode) == -1)

        goto fail;

    }

  }

#endif

  *fh = fdopen(fd, FOPEN_WRITETEXT);

  if(!*fh)

    goto fail;

  *tempname = tempstore;

  return CURLE_OK;

fail:

  if(fd != -1) {

    close(fd);

    unlink(tempstore);

  }

  free(tempstore);

  return result;

}

#endif /* ! disabled */